u-boot/drivers/i2c/sandbox_i2c.c

/*
 * Simulate an I2C port
 *
 * Copyright (c) 2014 Google, Inc
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <dm.h>
#include <errno.h>
#include <fdtdec.h>
#include <i2c.h>
#include <asm/test.h>
#include <dm/lists.h>
#include <dm/device-internal.h>
#include <dm/root.h>

DECLARE_GLOBAL_DATA_PTR;

struct dm_sandbox_i2c_emul_priv {
	struct udevice *emul;
};

static int get_emul(struct udevice *dev, struct udevice **devp,
		    struct dm_i2c_ops **opsp)
{
	struct dm_i2c_chip *plat;
	int ret;

	*devp = NULL;
	*opsp = NULL;
	plat = dev_get_parent_platdata(dev);
	if (!plat->emul) {
		ret = dm_scan_fdt_node(dev, gd->fdt_blob, dev->of_offset,
				       false);
		if (ret)
			return ret;

		ret = device_get_child(dev, 0, &plat->emul);
		if (ret)
			return ret;
	}
	*devp = plat->emul;
	*opsp = i2c_get_ops(plat->emul);

	return 0;
}

static int sandbox_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
			    int nmsgs)
{
	struct dm_i2c_bus *i2c = bus->uclass_priv;
	struct dm_i2c_ops *ops;
	struct udevice *emul, *dev;
	bool is_read;
	int ret;

	/* Special test code to return success but with no emulation */
	if (msg->addr == SANDBOX_I2C_TEST_ADDR)
		return 0;

	ret = i2c_get_chip(bus, msg->addr, 1, &dev);
	if (ret)
		return ret;

	ret = get_emul(dev, &emul, &ops);
	if (ret)
		return ret;

	/*
	 * For testing, don't allow writing above 100KHz for writes and
	 * 400KHz for reads
	 */
	is_read = nmsgs > 1;
	if (i2c->speed_hz > (is_read ? 400000 : 100000))
		return -EINVAL;
	return ops->xfer(emul, msg, nmsgs);
}

static const struct dm_i2c_ops sandbox_i2c_ops = {
	.xfer		= sandbox_i2c_xfer,
};

static const struct udevice_id sandbox_i2c_ids[] = {
	{ .compatible = "sandbox,i2c" },
	{ }
};

U_BOOT_DRIVER(i2c_sandbox) = {
	.name	= "i2c_sandbox",
	.id	= UCLASS_I2C,
	.of_match = sandbox_i2c_ids,
	.ops	= &sandbox_i2c_ops,
};